1. Renewable Transportation

2. PRODUCING ENERGY FROM BIOMASS
Plant materials
Animal wastes (#2)
burned to provide heat or electricity
Can be converted into gaseous or liquid biofuels

3. Converting Plants and Plant Wastes to Liquid Biofuels: An Overview
Motor vehicles can run on ethanol, biodiesel, and methanol produced from plants and plant wastes.
The major advantages of biofuels are:
Crops used for production can be grown almost anywhere.
There is no net increase in CO2 emissions.
Widely available and easy to store and transport.

4. Case Study: Producing Ethanol
Crops such as sugarcane, corn, and Switchgrass can be fermented to ethanol.
Also, agricultural, forestry, and municipal wastes
Switchgrass can remove CO2 from the troposphere and store it in the soil.

5. Case Study: Producing Ethanol
10-23% pure ethanol makes gasohol which can be run in conventional motors. (blend of ethanol and unleaded gasoline)
Ethanol (E85) is a mixture of 85% ethanol and 15% gasoline. fuel for flexible-fuel vehicles.
Biodiesel is made by combining alcohol with vegetable oil made from a variety of different plants.
Biodiesel from algae. Less land, not competing as a food source.

6. Some reduction in CO2 emissions Lower driving range
Trade-Offs
Ethanol Fuel
Advantages
Disadvantages
Large fuel tank needed
Some reduction in CO2 emissions
Lower driving range
Low net energy (corn)
High net energy (bagasse and switchgrass)
Much higher cost
Corn supply limited
Reduced CO emissions
May compete with growing food on cropland
Figure 17.27
Trade-offs: general advantages and disadvantages of using ethanol as a vehicle fuel compared to gasoline. QUESTION: Which single advantage and which single disadvantage do you think are the most important?
Can be sold as gasohol
Higher NO emissions
Potentially renewable
Corrosive
Hard to start in cold weather
Fig , p. 407

7. Slightly increased emissions of nitrogen oxides
Trade-Offs
Biodiesel
Advantages
Disadvantages
Reduced CO emissions
Slightly increased emissions of nitrogen oxides
Reduced CO2 emissions (78%)
Higher cost than regular diesel
Reduced hydrocarbon emissions
Low yield for soybean crops
Better gas mileage (40%)
May compete with growing food on cropland
High yield for oil palm crops
Figure 17.29
Trade-offs: general advantages and disadvantages of using biodiesel as a vehicle fuel compared to gasoline. QUESTION: Which single advantage and which single disadvantage do you think are the most important?
Loss and degradation of biodiversity from crop plantations
Moderate yield for rapeseed crops
Potentially renewable
Hard to start in cold weather
Fig , p. 408

8. Hybrid Vehicles
Hybrid gasoline-electric engines with an extra plug-in battery could be powered mostly by electricity produced by wind and get twice the mileage of current hybrid cars.
How does a Prius work?

9. Fuel-Cell Vehicles Video
Fuel-efficient vehicles powered by a fuel cell that runs on hydrogen gas are being developed.
Combines hydrogen gas (H2) and oxygen gas (O2) fuel to produce electricity and water vapor (2H2+O2  2H2O).
Emits no air pollution or CO2 if the hydrogen is produced from renewable-energy sources.
Hydrogen comes from electrolysis of water.

10. Body attachments Mechanical locks that secure the body to the chassis
Air system management
Universal docking connection Connects the chassis with the drive-by-wire system in the body
Fuel-cell stack Converts hydrogen fuel into electricity
Rear crush zone Absorbs crash energy
Drive-by-wire system controls
Cabin heating unit
Side-mounted radiators Release heat generated by the fuel cell, vehicle electronics, and wheel motors
Hydrogen fuel tanks
Front crush zone Absorbs crash energy
Figure 17.8
Solutions: prototype hydrogen fuel-cell car developed by General Motors. This ultralight and ultrastrong car consists of a skateboard-like chassis and a variety of snap-on fiberglass bodies. It handles like a high-speed sports car, zips along with no engine noise, and emits only wisps of warm water vapor and heat—no smelly exhaust, no smog, no greenhouse gases. General Motors claims the car could be on the road within a decade, but some analysts believe that it will be 2020 before this and fuel-cell cars from other manufacturers will be mass produced. (Basic information from General Motors)
Electric wheel motors Provide four-wheel drive; have built-in brakes
Fig. 17-8, p. 390

11. Converting to a Hydrogen Economy
Iceland plans to run its economy mostly on hydrogen
Produced via hydropower, geothermal, and wind energy
Doing this in industrialized nations is more difficult.
In the U.S. we would need the infrastructure for hydrogen-fueling stations
12,000 needed at $1 million apiece
High cost of fuel cells.